Wiper for machine tool

ABSTRACT

A wiper for machine tools includes an attachment portion  3  to be attached to a machine tool, wherein the machine tool is moved relative to a sliding surface  14 , and a wiper body  10  made of an elastic material integrated with the attachment portion  3 , wherein a lip portion  11  of the wiper body  10  can be slid on the sliding surface  14 , and a fabric material  5  is provided on at least a sliding surface side of the lip portion  1  of the wiper body  10 . The lip portion  11  has a low level of abrasion resistance, and a low level of abrasion loss is small. No damages are caused due to collision or impact with chips and a sliding surface does not suffer from damages or the like.

TECHNICAL FIELD

The present invention relates to a wiper for machine tools which isoperated on sliding surfaces of machine tools and industrial machines toscrape chips, cutting lubricants, and the like which are present on thesliding surfaces, for the purpose of preventing these chips and cuttinglubricants from entering the sliding surfaces.

BACKGROUND ART

Conventionally, a wiper used to remove chips and cutting lubricants froma machine tool includes a lip portion having a sliding portion which istypically made of a rubber material. The reason a rubber material isadopted is that the elasticity thereof is utilized to improve theconforming and scraping capabilities of the wiper in all directions.

Recently, a machine system which does not use a cutting lubricant (drycutting) in order to avoid environmental issues, a high-speed typemachine tool, and the like have been developed. Especially for thesemachines, a sliding portion of a wiper suffers from significant abrasiondue to the high coefficient of friction of rubber and therefore, thecloseness of the sliding portion of the wiper to the sliding surfacecannot long for a long time.

To address the above problem, a wiper including a sliding portion madeof thin spring steel has been proposed. However, when such a wiper istransported in a package made of corrugated cardboard, the wiper isoften deformed due to its thinness, causing inconvenience of handling.Further, when such a wiper is used, scattered chips strike and bend thespring steel, resulting in a reduction in the closeness of the wiper.Furthermore, since spring steel is a metallic material, sliding surfacesmay be damaged, or the spring steel may be corroded.

DISCLOSURE OF THE INVENTION

A wiper for machine tools according to ther present invention includesan attachment portion to be attached to a machine tool, wherein themachine tool is moved relative to a sliding surface, and a wiper bodymade of an elastic material integrated with the attachment portion. Alip portion of the wiper body can be slid on the sliding surface, and afabric material is provided on at least a sliding surface side of thelip portion of the wiper body.

In one embodiment, the fabric material is made of at least one materialselected from the group consisting of aromatic polyamide, aliphaticpolyamide, and polyester.

In one embodiment, the lip portion of the wiper body is covered with thefabric material.

In one embodiment, the fabric material is made of weave fabric or knitfabric, and a thickness of the fabric material is 0.5 mm or more.

In one embodiment, a fineness of a thread included in the fabricmaterial is 100 deniers or more.

In one embodiment, a coefficient of friction of a thread included in thefabric material is in the range of 0.1 to 0.3.

Since a fabric material is provided on at least a sliding side of a lipportion of a wiper, the coefficient of friction of the lip portion witha sliding surface is reduced and abrasion loss is reduced. Therefore,closeness can be maintained for a long time. Further, the lowcoefficient of friction allows the wiper to be slid at a high rate.Further, since a sliding portion of the lip portion includes a fabricmaterial, a sliding surface does not suffer from scratches which wouldbe otherwise observed when the sliding portion is made of a metallicmaterial. A defective product due to warpage of a wiper caused bycollision or impact with chips, or the like, can be avoided.

When a fabric material (fabric layer) to be abraded by fast slidingoperations has a small thickness, a wiper body made of an elasticmaterial, such as rubber, underlying the fabric material is exposed. Inthis case, friction resistance is increased and abrasion is rapidlyincreased.

To avoid this, the thickness of a fabric material (original fabric) isset to be 0.5 mm or more (particularly 1 mm or more), or the fineness ofa thread included in the fabric material is set to be 100 deniers ormore (particularly, the fineness of wefts extending in a directionperpendicular to a sliding direction is set to 400 deniers or more).Therefore, the life of the wiper can be lengthened in fast slidingoperations.

According to the present invention, at least a lip portion of a wiperbody is covered with a fabric material, whereby the friction resistanceof the lip portion is small and therefore a fast sliding operation canbe performed and the amount of leaked chips is small over long-term use.Further, since a sliding portion of the lip portion includes a fabricmaterial, a sliding surface does not suffer from scratches which wouldbe otherwise observed when the sliding portion is made of a metallicmaterial. A defective product due to warpage of a wiper caused bycollision or impact with chips, or the like, can be avoided.

Therefore, the wiper of the present invention can be used for machinetools which are moved at a high speed. Further, since scraping can besatisfactorily performed in an operation without cutting oil, the wiperof the present invention is applicable to particular operations, such asaluminum cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a wiper according to an embodimentof the present invention.

FIG. 2 is a cross-sectional view of a wiper according to anotherembodiment of the present invention.

FIG. 3 is a cross-sectional view of a wiper according to still anotherembodiment of the present invention.

FIG. 4 is a diagram for explaining a method for measuring a pressingforce of a wiper.

FIG. 5 is a diagram for explaining a method f or measuring a slidingresistance of a wiper.

FIG. 6 is a diagram for explaining a method for testing a slidingoperation of a wiper.

FIG. 7 is a cross-sectional view of a conventional wiper.

FIG. 8 is a cross-sectional view of another conventional wiper.

FIG. 9 is a cross-sectional view of a wiper according to still anotherembodiment of the present invention.

FIG. 10 is a cross-sectional view of a major portion of the wiper ofFIG. 9.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described with reference tothe accompanying drawings.

Referring to FIG. 1, a wiper 1 for machine tools according to thepresent invention includes an attachment portion 3 attached to a machinetool which is reciprocated with respect to a sliding surface 14 (e.g., amachine surface or a cover surface), and a wiper body 10 which is madeof an elastic material and is integrated with the attachment portion 3.

The attachment portion 3 is also called a cored bar and is typicallymade of a metallic material.

The wiper body 10 is formed as a long member which transversely extends.A lip portion 11 is provided at a lower portion of the wiper body 10, athickness of which is gradually decreased toward a tip side thereof.Preferably, the wiper body 10 is made of an elastic material, such asNBR, urethane rubber, fluorocarbon rubber, or H-NBR, is oil-resistant,and has a suitable elasticity in the hardness range of 70 to 90(typically 70).

For the wiper body 10, at least the lip portion 11 is covered with afabric material 5.

The fabric material 5 may be made of one or more synthetic fibers (e.g.,aliphatic polyamide, aromatic polyamide, and polyester), natural fiber,glass fiber, and metal fiber having a relatively low stiffness, andpreferably made of a synthetic fiber, such as aliphatic polyamide,aromatic polyamide, or polyester. The fabric material 5 may be in theform of weave fabric, knit fabric, or the like, and is preferably in theform of weave fabric.

Referring to FIG. 9, when the fabric material 5 is in the form of weavefabric or knit fabric, the thickness of the fabric material ispreferably in the range of 0.25 mm to 2.0 mm, more preferably 0.5 mm to1.5 mm, and even more preferably 0.5 mm to 1.0 mm. The fineness of thefibers of the fabric material is preferably in the range of 50 deniersto 500 deniers, and more preferably 100 deniers to 450 deniers.

Particularly, the fabric material 5 is provided at a sliding surfaceside of the lip portion 11 in such a manner that wefts 5 a of the weaveor knit fabric are orthogonal to a sliding direction of the lip portion11. As such, the fineness of the wefts 5 a is preferably in the range of80 deniers to 500 deniers, and more preferably 100 deniers to 450deniers. The fineness of the warps 5 b may be about half the fineness ofthe wefts 5 a, for example, 40 deniers to 250 deniers, and morepreferably 50 deniers to 200 deniers.

When the fineness of the wefts 5 a is thus greater than that of thewarps 5 b, the life of the wiper 1 can be lengthened in high-speedoperation. If the stiffness of a waist portion of the lip portion 11 isexcessively increased, the stiffness of the wiper itself is increasedand therefore the pressing force of the lip portion 11 is increased.This problem can be solved by the fineness of the warps 5 b beingsmaller than that of the wefts 5 a. Taking into consideration the linearshape of the edge of the lip portion 11, the area where the fabricmaterial 5 makes contact with the sliding surface is increased, so thatthe life of the wiper is expected to be lengthened.

The fabric material 5 may be subjected to adhesion treatment or rubberimpregnation treatment.

The fabric material 5 may be adhered to a lower surface of the lipportion 11 of the wiper body 10 using an adhesive or by vulcanization.

As shown in FIG. 1, the fabric material 5 may cover the wiper body 10,specifically, the lip portion 11 and a side surface of the wiper body10. As shown in FIGS. 2 and 3, upper and lower surfaces of the lipportion 11 of the wiper body 10 and the side surface of the wiper body10 may be covered with the fabric material 5.

Referring to FIG. 10, the fabric material 5 may be provided on the lowersurface (sliding surface) of the lip portion 11.

When the lip portion 11 of the wiper body 10, which is made of anelastic material (e.g., rubber), is thus protected by the fabricmaterial 5, the coefficient of friction of the lip portion 11 withrespect to the sliding surface 14 is smaller than that of a conventionallip portion of rubber without a fabric material cover. Therefore,abrasion loss can be reduced, whereby closeness can be maintained for along time. Although a conventional wiper including a sliding portionmade of a metallic material has a low level of sliding resistance, theamount of chips leaked during an actual sliding operation is larger inthe conventional wiper than in the wiper of the present invention. Awiper has a higher level of closeness when a sliding portion is made ofelastic rubber. In this case, the sliding resistance is smaller thanthat of conventional sliding portions than when the sliding portion ismade of a metallic material having a higher level of rigidity. Syntheticfibers used in weave fabric or the like have a small coefficient offriction (typically, 0.1 to 0.3). Synthetic fibers are also deformableand therefore do not hinder elastic deformation of the rubber.Therefore, the wiper 1 covered with the fabric material 5 made ofsynthetic fiber can be slid without losing closeness.

The outer surface of the lip portion 11 of the wiper body 10 is providedwith the fabric material 5, so that the fabric material 5 makes contactwith the sliding surface 14. Therefore, the frictional resistance of thewiper sliding portion is decreased, whereby abrasion can be reduced andthe sliding surface 14 is prevented from being damaged.

Next, an exemplary method for producing the wiper of the presentinvention will be described.

The fabric material 5 (e.g., weave fabric made of a synthetic resinfiber) is provided on a predetermined portion of a mold. The mold isfilled with unvulcanized rubber. The unvulcanized rubber is thenvulcanized. The wiper body 10 is thus produced and at the same time thefabric material 5 is vulcanized to be adhered to the wiper body 10. Inthis case, a portion of the unvulcanized rubber is vulcanized whilepermeating the fabric material 5 or passing through stitches of thefabric material 5, whereby the wiper body 10 and the fabric material 5are integrated together and therefore the adhesive strength therebetweenis enhanced.

As shown in FIGS. 1 to 3, the present invention is applicable to wipershaving various sizes and shapes for the purposes of removing chips andcoolant produced during operations of machine tools and industrialmachines.

EXAMPLES

Next, the present invention will be specifically described by way ofillustrative examples.

Evaluation methods which are used in the following examples will bedescribed below.

(1) Method for Measuring a Pressing Force of a Wiper

A. Testing Method

FIG. 4 shows a testing instrument. In FIG. 4, reference numeral 6indicates a load cell, reference numeral 7 indicates a saddle, andreference numeral 1 indicates a wiper.

The wiper 1 is fixed to the saddle 7. The wiper 1 is moved downwarduntil a tip portion of the lip portion 11 of the wiper 1 touches asurface of the load cell 6. The wiper 1 is further moved by 0.5 mm topress the load cell 6. A force exerted on the load cell 6 is sensed bythe load cell 6. Such a force is defined as a pressing force. Thepressing force is typically represented in units of per centimeter. Thepressing force is used as a vertical load (W) in the following section(manual resistance measurement).

B. Testing Conditions: No Lubricant

(2) Method for Measuring a Sliding Resistance of a Wiper

A. Testing Method

FIG. 5 shows a testing instrument. In FIG. 5, reference numeral 6indicates a load cell, reference numeral 7 indicates a saddle, referencenumeral 1 indicates a wiper, and reference numeral 8 indicates a slidingbed.

While the wiper 1 is fixed to the saddle 7, the sliding bed 8 is movedin a direction indicated by an arrow. A force F exerted on the load cell6 in a horizontal direction is sensed by the load cell 6. A coefficientof friction μ is calculated based on the force F and the vertical load W(a force generated when a wiper is pressed by a specified value of 0.5mm) in accordance with an expression:

F=μW

where F represents a sliding resistance (Kgf), μ represents acoefficient of friction, and W represents a pressing force (Kgf).

B. Testing Conditions:

No lubricant

Sliding rate of 10 m/min

(3) Method for Testing a Sliding Operation of a Wiper

A. Testing Method

FIG. 6 shows a specimen and a testing instrument. In FIG. 6, referencenumeral 7 indicates a saddle, reference numeral 1 indicates wipers,reference numeral 8 indicates a sliding bed, and reference numeral 3indicates cored bars of the wipers 1.

The wipers 1 are fixed on the opposite sides of the saddle 7 as shown inFIG. 6. The sliding bed 8 is reciprocated while chips 9 are confinedbetween the wipers 1. A distance traveled by a sliding portion 11 of thewiper 1 is calculated based on a sliding stroke of the sliding bed 8.The amount of chips which are leaked through the lip portions 11 of thewipers 1 and are present on the opposite ends of the sliding bed 8 ismeasured for different distances.

The wiper 1 used has the same cross-sectional shape as that of astandard product, and has a width of 120 mm. The wiper 1 is pressed by aspecified value of 0.5 mm (such a value is 3 mm for a wiper including asliding portion made of spring steel).

B. Testing Conditions:

No lubricant

Sliding rate of 25 m/min

Sliding stroke of 215 mm

Room temperature environment

Comparative Example 1

A cored bar was placed in a mold. The mold was filled with unvulcanizedNBR followed by vulcanization. A wiper including a cored bar 3 and awiper body 10 as shown in FIG. 7 was obtained.

This wiper was used, and the pressing force, sliding resistance and theamount of leaked chips were measured. The results are shown in Table 1.

Comparative Example 2

A wiper body 10 was made of NBR. A thin metal plate 12 was adhered to alower surface of a lip portion 11 of the wiper body 10 by vulcanization,thereby obtaining a wiper 1 as shown in FIG. 8.

The wiper 1 was used, and the pressing force, sliding resistance and theamount of leaked chips were measured. The results are shown in Table 1.

Example 1

A cored bar and a weave fabric made of synthetic fibers were placed in amold. The mold was filled with unvulcanized NBR followed byvulcanization. As a result, the wiper 1 including the cored bar 3 andthe wiper body 10 as shown in FIG. 1 was obtained. A lip portion 11 ofthe wiper body 10 was covered with the weave fabric 5.

The wiper 1 was used, and the pressing force, sliding resistance and theamount of leaked chips were measured. The results are shown in Table 1.

TABLE 1 Type of wiper Comparative Comparative Measured item Example 1Example 2 Example 1 Pressing force (gf/cm) 133 50 181 Sliding resistance(gf/cm) 71 19 48 Amount of  5 km of travel 0.06 0.10 0.05 leaked 15 kmof travel 0.12 0.16 0.09 chips in 30 km of travel 0.25 0.19 0.11 slidingtest (g)

The results shown in Table 1 indicate the following.

In Comparative Example 1, the lip portion of the wiper made only ofrubber had a high level of sliding resistance. The closeness of thewiper was lowered after long-term use, causing a large amount of leakedchips. In Comparative Example 2, the wiper including a sliding portionmade of a metallic material had a low level of sliding resistance. Theamount of leaked chips was small, but was larger than that of Example 1.Accordingly, when the sliding portion was made of elastic rubber, whichhas a sliding resistance smaller than that of Comparative Example 1(conventional wiper), instead of a metallic material having a high levelof rigidity, a higher level of closeness could be obtained.

In Example 1, rigid fibers, such as weave fabric, have smallcoefficients of friction. Rigid fibers are also deformable and thereforedo not hinder elastic deformation of the rubber. Therefore, a wiper canbe slid without losing closeness.

When as shown in Comparative Example 2, a sliding portion which is slidon a sliding surface is made of a metallic material, since a metallicmaterial has a smaller level of abrasion loss than that of rubber, theabrasion life is excellent. However, a rubber having a high level ofelasticity allows for a higher level of closeness than that of ametallic material having a high level of rigidity.

Example 2

A cored bar and a weave fabric made of synthetic fibers (nylon 6,6) wereplaced in a mold. The mold was filled with unvulcanized NBR followed byvulcanization. As a result, the wiper 1 including the cored bar 3 andthe wiper body 10 as shown in FIG. 10 was obtained. A sliding surface ofa lip portion 11 of the wiper body 10 was covered with the weave fabric5.

The weave fabric used had a thickness of 0.5 mm (measured for theoriginal fabric). The fineness of the wefts of the weave fabric was 100deniers, while the fineness of the warps of the weave fabric was 50deniers. The weave fabric was provided on a lower surface of the lipportion in such a manner that the wefts were provided orthogonal to asliding direction.

This wiper was used, and the abrasion resistance thereof was measuredunder the following conditions.

A. Testing Method

The testing instrument of FIG. 6 was used. In FIG. 6, reference numeral7 indicates a saddle, reference numeral 1 indicates wipers, referencenumeral 8 indicates a sliding bed, and reference numeral 3 indicates thecored bars of the wipers 1.

The wipers 1 were fixed on the opposite sides of the saddle 7 as shownin FIG. 6. The sliding bed 8 was reciprocated while chips 9 wereconfined between the wipers 1. A distance traveled by the wiper 1 wascalculated based on a sliding stroke of the sliding bed 8. The life ofthe wiper 1 was represented by the distance traveled by the wiper 1until abnormal noise occurred.

The wiper 1 used had the same cross-sectional shape as that of astandard product, and had a width of 120 mm. The wiper 1 was pressed bya specified value of 0.5 mm.

B. Testing Conditions:

No lubricant

Sliding rate of 80 m/min

Sliding stroke of 215 mm

Room temperature environment

As a result, the distance traveled by the wiper 1 until abnormal noiseoccurred was 650 Km.

Example 3

A fabric material (original fabric to be used for a fabric layer) had athickness of 1.0 mm, and the fineness of the wefts of the fabricmaterial was 420 deniers, while the fineness of the warps of the fabricmaterial was 210 deniers. In the other respects, a wiper of Example 3was the same as that of Example 2. The abrasion resistance of the wiperof Example 3 was measured.

As a result, the distance traveled by the wiper until abnormal noiseoccurred was 2000 km.

Comparative Example 3

A fabric material was not used, and the wiper obtained in ComparativeExample 1 was used. Except for this point, abrasion resistance wasmeasured in a manner similar to that of Example 2.

As a result, the distance traveled by the wiper until abnormal noiseoccurred was 30 km.

INDUSTRIAL APPLICABILITY

A wiper for machine tools is provided in which a lip portion has a lowlevel of abrasion resistance, and a low level of abrasion loss is small.A wiper for machine tools is provided in which no damages are caused dueto collision or impact with chips and a sliding surface does not sufferfrom damages or the like.

What is claimed is:
 1. A wiper for a machine tool comprising: anattachment portion to be attached to a the machine tool, wherein themachine tool is moved relative to a sliding surface; and a wiper bodymade of an elastic material integrated with the attachment portion,wherein a lip portion of the wiper body can be slid on the slidingsurface, the lip portion of the wiper body is covered with a fabricmaterial and a the fabric material is provided on at least a slidingsurface side of the lip portion of the wiper body, wherein the fabricmaterial is made of weave fabric, and wefts of the weave fabric beingorthogonal to the sliding direction of the lip portion, the fineness ofthe wefts being in the range of 80 to 500 deniers the fineness of thewarps being 40 deniers to 250 deniers, and the fineness of the warpsbeing smaller than that of the wefts.
 2. A wiper for a machine toolaccording to claim 1, wherein the fabric material is made of at leastone material selected from the group consisting of aromatic polyamide,aliphatic polyamide, and polyester.
 3. A wiper for a machine toolaccording to claim 1, wherein a thickness of the fabric material is 0.25mm or more.
 4. A wiper for a machine tool according to claim 1, whereina coefficient of friction of a thread included in the fabric material isin the range of 0.1 to 0.3.